Modulating Multiple Molecular Trajectories by Nutraceuticals and/or Physical Activity in Attention-Deficit/Hyperactivity Disorder (ADHD)-Like Behaviors in Rat Pups

Abstract

Attention deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition affecting cognitive and social functions all over childhood. Monosodium glutamate (MSG) is a common food additive associated with ADHD-like symptoms in children. Nutraceuticals, like sesamol (SE) and astaxanthin (AST), or physical activity (PHA) were reported to possess beneficial effects on human health. Meanwhile, still their neuroprotective effect against ADHD has been poorly investigated. This study aimed to investigate the impact of SE, AST and PHA either separately or combined on ADHD-like behaviors induced by MSG in rat pups. Eighty-four male Sprague Dawley rat pups were randomly allocated into seven groups; control, MSG, (PHA + MSG), (SE + MSG), (AST + MSG), (SE + AST + MSG), and (COMB [PHA + SE + AST] + MSG) and treated for eight weeks. MSG-induced ADHD-like behavior was evaluated, via assessing behavioral outcomes; neurotransmitters' levels; five pathway biomarkers, coupled with histopathological and immunohistochemical studies. Rats exposed to PHA or treated with SE or AST either separately or combined exhibited enhanced attention, locomotor, and cognitive abilities, compared to MSG-intoxicated group. All treatments remarkably improved MSG-induced abnormalities in neurotransmitters' levels; biochemical markers; along with histological findings, via modulating HMGB1/RAGE/JAK-2/STAT-3, PI3K/AKT/CREB/BDNF, AMPK/SIRT-1 and PERK/CHOP pathways. Nevertheless, the combination of PHA with nutraceuticals (SE and AST) elicited more favorable effects in all measured parameters and histological findings, compared to other treated groups. In conclusion, this study revealed the superiority of the combination of nutraceuticals with PHA, over other standalone treatments, in amelioration of MSG-induced ADHD-like behaviors in rat pups, via fine-tuning of HMGB1/RAGE, PI3K/AKT/CREB/BDNF, AMPK/SIRT-1 and PERK/CHOP pathways.

Keywords: ADHD; Astaxanthin; Autophagy; Endoplasmic reticulum stress; Monosodium glutamate; Physical activity; Sesamol.

Fig. 1

Effects of SE, AST and PHA on MSG-induced behavioral changes in (A) Latency Time, (B) Ambulation Frequency and (C) Grooming Frequency in open-field test and (D) Spontaneous alteration percentage in Y-maze test. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Spontaneous alteration percentage (SAP)

Fig. 2

Effects of SE, AST and PHA on brain neurotransmitters in MSG-intoxicated rats: (A) DA, (B) NE, (C) 5-HT and (D) Glutamate. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Dopamine (DA); Norepinephrine (NE) and Serotonin (5-HT)

Fig. 3

Effects of SE, AST and PHA on brain oxidative stress biomarkers in MSG-intoxicated rats: (A) MDA, (B) SOD and (C) TAC. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Malondialdehyde (MDA); Superoxide dismutase (SOD) and Total antioxidant capacity (TAC)

Fig. 4

Effects of SE, AST and PHA on brain neuroinflammatory biomarkers in MSG-intoxicated rats: (A) TNF-α and (B) IL-1β. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Interleukin-1β (IL-1β) and Tumor necrosis factor-alpha (TNF-α)

Fig. 5

Effects of SE, AST and PHA on HMGB1/RAGE and JAK-2/STAT-3 signaling pathways in MSG- intoxicated rats: (A) HMGB1, (B) RAGE, (C) JAK-2 and (D) STAT-3. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); High mobility group box 1 (HMGB1); Receptor for Advanced Glycation End Products (RAGE); Janus kinase-2 (JAK-2) and Signal transducer and activator of transcription-3 (STAT-3)

Fig. 6

Effects of SE, AST and PHA on AMPK/SIRT-1 and CREB/BDNF/TrkB signaling pathways in MSG-intoxicated rats: (A) AMPK, (B) SIRT-1, (C) BDNF, (D) TrkB and (E) CREB. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); AMP-enhanced protein kinase (AMPK); Sirtuin-1 (SIRT-1); Brain-derived neurotrophic factor (BDNF); Tropomyosin receptor kinase B (TrKB); Cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB)

Fig. 7

Effects of SE, AST and PHA on PI3K/AKT and m-TOR/Beclin-1 signaling pathways in MSG-intoxicated rats: (A) Beclin-1, (B) PI3K, (C) AKT and (D) m-TOR. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Phosphoinositide 3-kinase (PI3K); Protein kinase B (AKT); Mechanistic target of rapamycin (m-TOR)

Fig. 8

Effects of SE, AST, and PHA on PERK/GRP78/CHOP and BAX/Bcl-2 signaling pathways in MSG-intoxicated rats: (A) PERK, (B) GRP78, (C) CHOP, (D) BAX and (E) Bcl-2. The data are presented as means ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P-value < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Protein kinase RNA-like ER kinase (PERK), Glucose-regulated protein 78 (GRP78), Pro-apoptotic C/EBP homologous protein (CHOP), Bcl-2-associated X protein (BAX), B-cell lymphoma 2 protein (Bcl-2)

Fig. 9

Effects of SE, AST and PHA on MSG-induced histopathological changes in brain tissues. Represented photomicrographs of brain sections stained by Hematoxylin and Eosin (magnification 40 X) of Control (A), MSG (B), PHA + MSG (C), SE + MSG (D), AST + MSG (E), SE + AST + MSG (F) and SE + AST + PHA + MSG (G) groups, showed different histopathological alteration in the cerebral cortex, striatum, hippocampus (fascia dentate and subiculum) and substantia nigra. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA)

Fig. 10

Effects of SE, AST and PHA on GFAP immunoexpression in the brain of MSG-intoxicated rats. Illustrative photomicrograph of immunohistochemical staining of GFAP-positive cells in the brain (arrows). Control group (A), MSG group (B), PHA + MSG group (C), SE + MSG group (D), AST + MSG group (E) SE + AST + MSG group (F), and COMB + MSG group (G) [× 200]. Bar chart represents the area % of GFAP staining in the different groups (H). Data are presented as mean ± S.E.M (n = 6). Significance (a): relative to the control group, (b): relative to MSG group, (c): relative to PHA + MSG, (d): relative to SE + MSG, (e): relative to AST + MSG, and (f): relative to SE + AST + MSG. P < 0.05. Monosodium glutamate (MSG); Physical activity (PHA); Sesamol (SE); Astaxanthin (AST); COMB (SE + AST + PHA); Glial fibrillary acidic protein (GFAP)